powerpc: Rate-limit users spamming kernel log buffer

The facility unavailable exception can be triggered from userspace by
accessing PMU registers when EBB is not enabled.  This causes the
included pr_err() to run, hence spamming the kernel log buffer.

This avoids this by rate limiting these messages.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 33cd7a0b8e73..df86f0ce2d36 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1379,8 +1379,9 @@ void facility_unavailable_exception(struct pt_regs *regs)
         if (!arch_irq_disabled_regs(regs))
                 local_irq_enable();
 
-        pr_err("%sFacility '%s' unavailable, exception at 0x%lx, MSR=%lx\n",
-               hv ? "Hypervisor " : "", facility, regs->nip, regs->msr);
+        pr_err_ratelimited(
+                "%sFacility '%s' unavailable, exception at 0x%lx, MSR=%lx\n",
+                hv ? "Hypervisor " : "", facility, regs->nip, regs->msr);
 
         if (user_mode(regs)) {
                 _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);